How do you make a armature and connect it to a mesh?
If you have an armature ready to go, then in Object mode, select the mesh and then shift select the armature. Then press Cmd+P/Ctrl+P and parent it with automatic weights.
Now you can select the armature and move the individual bones in Pose mode and the mesh should move with it. If certain bones have too much/too little influence on the mesh, you can alter it by selecting the mesh, going to Weight Paint mode, and select the bone that you want to edit in the Object Data Properties tab under Vertex Groups.
It might also be useful to apply some inverse kinematics to your armature to make animation easier and more realistic. Blender has a good video tutorial on how to do that here and this one is also useful.
As mentioned previously, this YouTube playlist is a really helpful resource that walks through almost every aspect of adding and editing armatures.